Many types of input devices are available for performing operations in a computing system, such as buttons or keys, mice, trackballs, touch sensor panels, joysticks, touch pads, touch screens, and the like. Touch sensitive devices, and touch screens, in particular, are becoming increasingly popular because of their ease and versatility of operation as well as their declining price. Touch sensitive devices can include a touch sensor panel, which can be a clear panel with a touch sensitive surface, and a display device such as a liquid crystal display (LCD) that can be positioned partially or fully behind the panel, or integrated with the panel, so that the touch sensitive surface can substantially cover at least a portion of the viewable area of the display device. Touch sensitive devices can generally allow a user to perform various functions by touching or hovering over the touch sensor panel using one or more fingers, a stylus or other object at a location often dictated by a user interface (UI) including virtual buttons, keys, bars, displays, and other elements, being displayed by the display device. In general, touch sensitive devices can recognize a touch event and the position of the touch event on the touch sensor panel or a hover event and the position of the hover event on the touch sensor panel, and the computing system can then interpret the touch or hover event in accordance with the display appearing at the time of the event, and thereafter can perform one or more operations based on the event.
The ability to recognize and interpret the touch or hover event can be compromised by noise introduced into the touch sensitive device by various components. However, it can be challenging to substantially reduce or eliminate the noise so that the touch sensitive device can perform touch and hover operations effectively and efficiently.